In chilling letters, allegedly written by the late al Qaeda son Hamza, the 28 year old was all about Vengeance for the death of his terrorist father.

According to reports, Osama bin Laden's son has vowed to avenge his father's death with a cryptic and chilling threat: "Americans, we're coming and you're going to feel it."

In personal letters found after the 2011 raid that killed his father, Hamza bin Laden, now in his late 20s, is said to have written the following words: "We're going to take revenge for what you did to my father...Iraq...Afghanistan."

The threat filled letters, discovered in his compound in Pakistan after he was killed by Navy Seals in 2011, also said: "Every look...every smile you gave me, every word you told me. I consider myself to be forged in steel. The path of jihad for the sake of God is what we live for."

These claims were made by ex- FBI agent Ali Soufan who used to be the lead investigator on the terror groupafter 9/11 in a forthcoming episode of American news show 60 Minutes.

Hamza who used to be a poster child for al Qaeda Propaganda while Bin Laden was alive and even after his death, has been pictured and Videod several times through the years.